#!/bin/sh

usage() {
	printf "Usage: %s [-h] -f /path/to/CHANGELOG.md\n" "$0"
}

help() {
    cat << EOH
 SYNOPSIS
    $0 [-h] -f /path/to/CHANGELOG.md

 DESCRIPTION

    $0 generates a markdown content of a changelog file.

 OPTIONS

    -h    Show this help

    -f FILE
	      Path to changelog
EOH
}

on_interrupt() {
	print "Process aborted!\n"

	exit 130
}

main() {
	while getopts "hf:" option; do
		case "${option}" in
			h) help; exit 0;;
			f) CHANGELOG_FILE="$OPTARG";;
			*) usage; exit 1;;
		esac
	done

	if [ -z "$CHANGELOG_FILE" ]; then
		printf "The file of the changelog is required.\n"
		exit 1
	fi

	if [ ! -f "$CHANGELOG_FILE" ]; then
		printf "No such file: %s\n" "$CHANGELOG_FILE"
		exit 1
	fi

	temp_directory="$(mktemp -d)"
	version=
	is_first=1

	cat << EOF
---
hide:
  - toc
---

# Changelog

EOF


	while read -r line; do
		if printf "%s" "$line" | grep -q -E '^## '; then
			version="$(printf "%s" "$line" | sed 's/^## //')"

			if [ "$version" = "[Unreleased]" ]; then
				version=""
			fi
		elif [ -n "$version" ]; then
			printf "%s\n" "$line" >> "$temp_directory/$version"
		fi
	done < "$CHANGELOG_FILE"

	while read -r line; do
		if printf "%s" "$line" | grep -q -E '^## '; then
			version="$(printf "%s" "$line" | sed 's/^## //')"

			if [ "$version" != "[Unreleased]" ]; then
				if [ $is_first -eq 1 ]; then
					printf "???+ success \"%s\"\n" "$version"
					is_first=0
				else
					printf "??? abstract \"%s\"\n" "$version"
				fi

				sed \
					-e 's/### \(.*\)/\n    **\1**\n/g' \
					-e 's/^/    /g' \
					"$temp_directory/$version"
			fi
		fi
	done < "$CHANGELOG_FILE"

	exit 0
}

trap on_interrupt INT

main "$@"